How do you get rid of black algae in aquarium plants?

To get rid of black algae (likely Black Beard Algae, or BBA) on aquarium plants, the most direct method is to use hydrogen peroxide. Here's how:

1. Remove the affected plant: Carefully take the plant showing signs of black algae out of your aquarium. This is crucial to prevent the hydrogen peroxide from harming beneficial bacteria and other inhabitants of your tank. Also remove any affected hardscape.

2. Hydrogen Peroxide Treatment: Fill a squirt bottle with 3% hydrogen peroxide (the kind you find at the drugstore). Thoroughly spray the black algae-covered areas of the plant and/or hardscape.

3. Wait a Few Minutes: Allow the hydrogen peroxide to sit on the affected areas for approximately 5-10 minutes. Keep a close watch for any signs of plant damage during this time.

4. Rinse Thoroughly: After the waiting period, rinse the plant and/or hardscape very well with dechlorinated water. This step is important to remove any residual hydrogen peroxide that could harm your aquarium's ecosystem.

5. Return to Aquarium: Once you've rinsed the treated items thoroughly, you can safely return it to your aquarium.

Important Considerations:

• Spot Treatment in Tank (Use with Caution): Although removing the plant is the preferred method, you can spot-treat BBA directly in the aquarium using a syringe to apply hydrogen peroxide. However, use extreme caution. A general rule is to not exceed 1ml of 3% hydrogen peroxide per gallon of aquarium water. Turn off your filters during application and target only the affected areas. Monitor your fish and invertebrates closely for any signs of distress.

• Excel/Glutaraldehyde: Seachem Excel (or other liquid carbon supplements containing glutaraldehyde) can also be effective against BBA. Use according to the product instructions. This method is generally less harsh than hydrogen peroxide but may take longer to show results. It can be applied directly to the tank.

• Cause of Black Algae: Black algae growth is often linked to imbalances in your aquarium, such as:

  • Poor water circulation
  • Excess nutrients (nitrates, phosphates)
  • Low or fluctuating CO2 levels (in planted tanks)
  • Inconsistent lighting schedules

• Prevention: To prevent black algae from returning, address the underlying causes:

  • Ensure proper water circulation with a strong filter or powerhead.
  • Regularly test your water parameters and perform water changes to maintain nutrient levels.
  • If you have a planted tank, maintain stable CO2 levels.
  • Provide consistent lighting.